Systems and methods for cleanable and slip resistant tile

ABSTRACT

Disclosed herein are floor tiles comprising, for instance, a substrate and a surface coating, wherein the surface coating comprises (i) a base formula comprising a glaze and (ii) particles comprising alumina trihydrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 120 to U.S. patentapplication Ser. No. 14/444,316, filed 28 Jul. 2014, which claimspriority under 35 U.S.C. § 119(e) to U.S. Provisional Patent ApplicationNo. 61/859,550, filed 29 Jul. 2013, and titled “Systems and Methods forCleanable and Slip Resistant Tile,” the entire contents and substance ofeach of which is hereby incorporated by reference as if fully set forthbelow.

BACKGROUND 1. Field of the Invention

Embodiments of this disclosure relate to tile systems and methods, andmore particularly, to systems and methods for cleanable, slip resistanttile.

2. Description of Related Art

A variety of tile systems and methods are known. In general, tile is amanufactured material used for covering floors, walls, roofs, and othersimilar areas. In many situations, tile can provide a desirableappearance, texture, feel, or other surface characteristic that isdifficult or impossible to achieve by other means. Tiles are commonlymade from ceramic materials, although they can be made from a variety ofother materials such as wood, stone, metal, and glass. Moreover, tilescommonly have coatings that influence the surface characteristics of thetile. Some coatings, for example, can influence the color, roughness, orgloss of the tile.

Two important characteristics of a tile are (1) the ability to clean thetile (the “clean-ability” of the tile) and (2) the slip resistance ofthe tile. Clean-ability is important because dirty tiles are rarelydesirable. In circumstances where tile is used on a floor, wall, orroof, for example, the tile will likely become dirty over time, and itwill likely become desirable to clean the tile so that the tile providesa desired appearance. In addition, the slip resistance of a tile can beimportant to prevent people, machines, or other objects from slipping onthe tile. In many circumstances, for example, it is desirable to preventpeople from slipping on a tile floor, especially when the floor is wet.

Existing tiles and existing tile coatings do not provide for tiles thathave both high clean-ability and high slip resistance. This is because,in conventional designs, as the slip resistance of the tile increasesthe clean-ability decreases, and as the clean-ability increases the slipresistance decreases. In other words, clean-ability and slip resistancetypically have an inverse relationship because the surface that isrequired to optimize either cannot optimize the other. The rule of thumbis that a rough and textured surface has high slip resistance and lowclean-ability, whereas a smooth and glassy surface has highclean-ability and low slip resistance.

What is needed, therefore, is a tile, tile coating, or similar coatingthat provides both high clean-ability and high slip resistance. It is tothis need that embodiments of this disclosure are primarily directed.

BRIEF SUMMARY

Briefly described, embodiments of this disclosure comprise a tile thatis both highly cleanable and slip resistant. The tile can comprise asurface coating. The surface coating can comprise a base formula thathas particles dispersed therein. The structure and chemistry of thesurface coating and particles can enable the coating to be fired athigh, desirable temperatures and to exhibit high clean-ability and highslip resistance.

Embodiments of this disclosure can comprise a tile that can comprise asubstrate and a surface coating. In some embodiments, the surfacecoating can comprise a base formula. In some embodiments, the surfacecoating can comprise particles comprising alumina-zirconium-silicate. Insome embodiments, the surface coating can comprise particles comprisingtabular alumina. In some embodiments, the surface coating can compriseparticles comprising alumina trihydrate. In some embodiments, thesurface coating can comprise particles comprising tabular alumina andparticles comprising alumina trihydrate.

In some embodiments, the weight of particles comprisingalumina-zirconium-silicate and the weight of particles comprisingalumina trihydrate can be substantially equal. In some embodiments, theweight ratio of particles comprising alumina-zirconium-silicate toparticles comprising alumina trihydrate to particles comprising tabularalumina can be from 3:3:1 to 5:5:1. In some embodiments, the weightratio of particles comprising alumina-zirconium-silicate to particlescomprising alumina trihydrate to particles comprising tabular aluminacan be approximately 4:4:1.

In some embodiments, substantially all of the particles can have adiameter less than 33.011 μm. In some embodiments, about 90% of theparticles can have a diameter less than 20.0436 μm. In some embodiments,about 50% of the particles can have a diameter less than 7.25089 μm.

In some embodiments, the tile can comprise a base coating disposedsubstantially between the substrate and the surface coating. In someembodiments, the base coating can support the surface coating during afiring process, even when at least a portion of the firing processoccurs at above 1150 degrees Celsius. In some embodiments, the surfacecoating can provide a clean-ability ΔE of 0.6 to 1.0 and a dynamiccoefficient of friction of 0.60 to 0.95. In some embodiments, the baseformula can comprise NB-0022 glaze.

Embodiments of this disclosure can also comprise a tile comprising asubstrate. In some embodiments, the tile can further comprise a surfacecoating that can form a surface of the tile. In some embodiments, thesurface coating can provide a clean-ability ΔE of 0.6 to 1.0 and adynamic coefficient of friction of 0.60 to 0.95. In some embodiments, anaverage root mean square roughness (RMS) of the tile can be between 11.5μm and 12.6 μm. In some embodiments, an average of the average roughness(Ra) of the tile can be between 9.5 μm and 11.0 μm.

Embodiments of this disclosure can also comprise a floor tile comprisinga substrate and a surface coating. In some embodiments, the surfacecoating of the floor tile can comprise a base formula comprising aglaze; and particles comprising alumina trihydrate.

In some embodiments, the surface coating of the floor tile furthercomprises particles comprising tabular alumina. In other embodiments,the surface coating further comprises particles comprisingalumina-zirconium-silicate.

In some embodiments, the weight of particles comprisingalumina-zirconium-silicate and the weight of particles comprisingalumina trihydrate is substantially equal.

In some embodiments, the surface coating of the floor tile furthercomprises particles comprising alumina-zirconium-silicate and particlescomprising tabular alumina. In some embodiments, the weight ratio ofparticles comprising alumina-zirconium-silicate to particles comprisingalumina trihydrate to particles comprising tabular alumina is from 3:3:1to 5:5:1. In some embodiments, the weight ratio of particles comprisingalumina-zirconium-silicate to particles comprising alumina trihydrate toparticles comprising tabular alumina is approximately 4:4:1.

In some embodiments, substantially all of the particles have a diameterless than 33.011 μm. In some embodiments, about 90% of the particleshave a diameter less than 20.0436 μm. In some embodiments, about 50% ofthe particles have a diameter less than 7.25089 μm.

In some embodiments, the floor tile further comprises a base coatingdisposed substantially between the substrate and the surface coating. Insome embodiments, the base coating of the floor tile supports thesurface coating during a firing process, wherein at least a portion ofthe firing process occurs at above 1150° C.

In some embodiments, the surface coating of the floor tile provides aclean-ability ΔE of 0.6 to 1.0 and a dynamic coefficient of friction of0.60 to 0.95.

In some embodiments, the glaze comprises a frit, a clay, and anopacifier.

In some embodiments, an average RMS of the floor tile is between 11.5 μmand 12.6 μm. In some embodiments, an average Ra of the floor tile isbetween 9.5 μm and 11.0 μm. In some embodiments, an average RMS of thefloor tile is between 11.5 μm and 12.6 μm and an average Ra of the floortile is between 9.5 μm and 11.0 μm.

In some embodiments, the solid particles make up from 2% to 10% of theweight of the surface coating. In some embodiments, the solid particlesmake up from 7% to 15% of the weight of the surface coating. In someembodiments, the solid particles make up from 1% to 25% of the weight ofthe surface coating.

Embodiments of this disclosure can also comprise a method of making atile. In some embodiments, the method can comprise providing a substrateas a first layer of the tile. In some embodiments, the method canfurther comprise providing a surface coating as a second layer of thetile, and the surface coating can comprise a base formula and haveparticles mixed into the base formula. In some embodiments, the methodcan further comprise firing the tile at a temperature above 1150 degreesCelsius. In some embodiments, the method can further comprise firing thetile at a temperature above 1230 degrees Celsius. In some embodiments,the method can further comprise providing a base coating as a thirdlayer of the tile. In some embodiments, the base coating can be disposedsubstantially between the substrate and the surface coating, and thebase coating can support the surface coating during the entire firingprocess.

These and other embodiments of this disclosure are described in theDetailed Description below and the accompanying figures. Otherembodiments and features of embodiments of this disclosure will becomeapparent to those of ordinary skill in the art upon reviewing thefollowing Detailed Description in concert with the figures. Whilefeatures of this disclosure may be discussed relative to certainembodiments and figures, all embodiments of this disclosure can includeone or more of the features discussed herein. While one or moreembodiments may be discussed as having certain advantageous features,one or more of such features may also be used with the variousembodiments of the invention discussed herein. In similar fashion, whileexemplary embodiments may be discussed as system or method embodiments,it is to be understood that such exemplary embodiments can beimplemented in various devices, systems, and methods of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features and advantages of this disclosure may be more readilyunderstood with reference to the following Detailed Description taken inconjunction with the accompanying drawing figures, wherein likereference numerals designate like structural elements, and in which:

FIG. 1A depicts a tile with improved clean-ability and slip resistance,in accordance with some embodiments of this disclosure.

FIG. 1B depicts an exploded view of the tile of FIG. 1A, in accordancewith some embodiments of this disclosure.

FIG. 1C depicts a close-up of cross-section C-C of the tile of FIG. 1A,in accordance with some embodiments of this disclosure.

FIG. 2A depicts an interferometer output showing a three-dimensionalview of the surface structure of the tile of FIG. 1A, in accordance withsome embodiments of this disclosure.

FIG. 2B depicts an interferometer output that illustrates atwo-dimensional, overhead view of the surface structure of the tile ofFIG. 1A, in accordance with some embodiments of this disclosure.

FIG. 2C is a graph generated by an interferometer that shows the surfacestructure of the tile of FIG. 1A, in accordance with some embodiments ofthis disclosure.

FIG. 3A depicts an interferometer output showing a three-dimensionalview of the surface structure of a conventional tile.

FIG. 3B depicts an interferometer output that illustrates atwo-dimensional, overhead view of the surface structure of theconventional tile of FIG. 3A.

FIG. 3C is a graph generated by an interferometer that shows the surfacestructure of the conventional tile of FIG. 3A.

FIG. 4 is a graph showing size distribution of particles in a surfacecoating, in accordance with some embodiments of this disclosure.

FIG. 5 is a graph showing sintering properties and viscosity propertiesof a desirable base coating over a range of firing temperatures, inaccordance with some embodiments of this disclosure.

FIG. 6 is a graph showing sintering properties and viscosity propertiesof an undesirable base coating over a range of firing temperatures.

FIG. 7 is a graph showing a comparison of viscosity properties of adesirable base coating and an undesirable base coating.

DETAILED DESCRIPTION

To facilitate an understanding of the principles and features of thevarious embodiments of the invention, various illustrative embodimentsare explained below. Although exemplary embodiments of the invention areexplained in detail as being systems and methods for cleanable and slipresistant tile, it is to be understood that other embodiments arecontemplated, such as embodiments employing other types of surfaces,coatings, tiles, or tile manufacturing methods. Accordingly, it is notintended that the invention is limited in its scope to the details ofconstruction and arrangement of components set forth in the followingdescription or examples. The invention is capable of other embodimentsand of being practiced or carried out in various ways. Also, indescribing the exemplary embodiments, specific terminology will beresorted to for the sake of clarity.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferences unless the context clearly dictates otherwise. For example,reference to a component is intended also to include composition of aplurality of components. References to a composition containing “a”constituent is intended to include other constituents in addition to theone named.

Also, in describing the exemplary embodiments, terminology will beresorted to for the sake of clarity. It is intended that each termcontemplates its broadest meaning as understood by those skilled in theart and includes all technical equivalents which operate in a similarmanner to accomplish a similar purpose.

Ranges may be expressed herein as from “about” or “approximately” or“substantially” one particular value and/or to “about” or“approximately” or “substantially” another particular value. When such arange is expressed, other exemplary embodiments include from the oneparticular value and/or to the other particular value.

By “comprising” or “containing” or “including” is meant that at leastthe named compound, element, particle, or method step is present in thecomposition or article or method, but does not exclude the presence ofother compounds, materials, particles, method steps, even if the othersuch compounds, material, particles, method steps have the same functionas what is named.

It is also to be understood that the mention of one or more method stepsdoes not preclude the presence of additional method steps or interveningmethod steps between those steps expressly identified. Similarly, it isalso to be understood that the mention of one or more components in acomposition does not preclude the presence of additional components thanthose expressly identified.

The materials described as making up the various elements of theinvention are intended to be illustrative and not restrictive. Manysuitable materials that would perform the same or a similar function asthe materials described herein are intended to be embraced within thescope of the invention. Such other materials not described herein caninclude, but are not limited to, for example, materials that aredeveloped after the time of the development of the invention.

To facilitate an understanding of the principles and features of thisdisclosure, various illustrative embodiments are explained below. Inparticular, various embodiments of this disclosure are described ascleanable and slip resistant tile and related methods. Some embodimentsof the invention, however, may be applicable to other contexts, andembodiments employing these embodiments are contemplated. For example,and not limitation, some embodiments of the invention may be applicableto various types of surfaces, floor or ceiling coatings, other surfacecoatings, or other types of surfaces altogether. Accordingly, whereterms such as “tile” or “coating” or “floor” or related terms are usedthroughout this disclosure, it will be understood that other devices,entities, objects, or activities can take the place of these in variousembodiments of the invention.

As described above, a problem with existing tile systems and methods isthat they do not provide both high clean-ability and high slipresistance. This is because, traditionally, clean-ability and slipresistance have an inverse relationship. Thus, in conventional tile andflooring designs, a rough and textured surface provides high slipresistance and low clean-ability, and a smooth and glassy surfaceprovides high clean-ability and low slip resistance.

The present disclosure, however, describes tiles, coatings, and relatedmethods that provide both high clean-ability and high slip resistance.Thus, the tiles, coatings, and methods of this disclosure can providethe advantages of being easy to clean and preventing slipping.

There are several different methods that can be used to evaluate theclean-ability and slip resistance of a flooring material, such as atile. These methods can be helpful to quantify the clean-ability and theslip resistance, such that these qualities can be compared to othertiles.

Clean-ability can be defined as the ease with which a surface can becleaned. A high clean-ability represents a surface that is relativelyeasy to clean, while a low clean-ability represents a surface that isrelatively difficult to clean. The methods for measuring clean-abilityfrequently involve measuring the color difference caused by theapplication of a staining material on a surface. The staining materialcan be, for example and not limitation, any liquid or solid that is notrepelled by a typical ceramic surface and that is a contrasting colorwhen compared to the surface. Dark grout, for example, can be a stainingmaterial for a very light-colored tile.

To measure clean-ability, the color of the flooring material is firstmeasured when clean. A staining material is then applied, and a cleaningroutine is undergone to attempt to remove the staining material. Asecond color measurement is then taken. The color difference between thefirst measurement and the second measurement is then calculated.

The color difference can be calculated in a variety of ways. Typically,color measurements are made using the L*, a*, b* color space (CIELAB),as will be known by those of skill in the art to which this disclosurepertains. Thus, the color difference of an individual point can becalculated using the vector ΔE*, which reflects the difference in thelength of the vector between the L*, a*, and b* points before and afterthe staining and cleaning. When looking at a whole tile, an average ΔE*,termed ΔE or clean-ability ΔE, can be calculated and used to determinethe clean-ability of the tile. A high ΔE indicates a tile with lowclean-ability, and a low ΔE indicates a tile with high clean-ability.Using this method, traditional tiles have a clean-ability ΔE of between1.0 and 2.0. A tile with high clean-ability can have a ΔE of less thanor equal to 1.0, and a tile with low clean-ability can have a ΔE of 2.0or more.

To measure slip resistance, a coefficient of friction, or COF, iscommonly used. As will be known by those of skill in the art, the COF isa measurement which indicates the amount of traction a surface exerts toan object on the surface. Surfaces typically have static a static COF,or SCOF, and a dynamic COF, or DCOF. The SCOF can be the initial COFexerted by a surface on an object that is stationary. The DCOF can bethe COF exerted by a surface on an object that is moving across thesurface. High COF values typically coincide with high slip resistance.

One method for measuring the COF of ceramic and similar flooringsurfaces is ASTM B101.3, which is a standard from the American Societyfor Testing Materials. ASTM B101.3 can be used to measure the DCOF whenthe flooring is wet. In many countries, the wet DCOF is typically themost important measurement in slip-and-fall investigations because themeasurement typically reveals a worst-case scenario of the flooring(i.e., the most slippery state of the flooring that is commonlyencountered). This is because, when wet, the DCOF of a flooring materialcan become less dependent on the pressure between the flooring surfaceand the moving object and can lower the DCOF as a result. A typicalvalue of the DCOF for a wet ceramic floor tile is approximately 0.42.This is the minimum acceptable value in many commercial markets, such asthose in the United States. A tile that has high slip resistance canhave a wet DCOF of at least 0.60, and a tile with low slip resistancecan have a wet DCOF of below 0.42.

Known tiles and coatings do not provide a flooring material with a highwet DCOF (and thus high slip resistance) that also has highclean-ability. Generally, as the wet DCOF increases the clean-abilitydecreases. The two properties typically have an inverse relationshipbecause the surface that is required to optimize either cannot optimizethe other. A rough and textured surface is generally hard to cleanbecause the stain material, and other undesirable materials, can betrapped within the narrow crevices of the surface. A smooth and glassysurface is generally slippery because it does not have micro- ormacro-structures (peaks and valleys) with which another material, forexample the sole of a shoe, can interact and interlock. A product thatprovides high slip resistance and a high clean-ability could be idealfor a high traffic or commercial area where there is significant concernfor slipping on wet surfaces and the desire for a clean floor. Such aproduct could also be ideal for in-home use, as it could preventresidents and their guests from slipping and failing and sustaininginjury, while nevertheless enabling the floor to be easily cleanable.

Embodiments of the present disclosure provide such tiles, coatings, andrelated methods. In some embodiments, wet DCOFs at or greater than 0.60can be achieved while having a clean-ability ΔE that is equal to or lessthan 1.0.

FIG. 1A shows a tile 100 in accordance with some embodiments of thisdisclosure. FIG. 1B shows an exploded view of the tile 100 of FIG. 1A,and FIG. 1C shows a close-up of cross-section C-C of the tile 100 ofFIG. 1A. As can be seen in FIGS. 1A-1C, the tile 100 can have asubstrate 105, an optional base coating 110, and a surface coating 115.Without being bound by any particular theory, in some embodiments, thesurface structure of the surface coating 115 can enable the tile 100 toprovide the properties of high clean-ability and high slip resistance.More specifically, the height, shape, and transition between “peaks” 120and “valleys” 125 in the surface coating 115 can provide theseproperties.

Those of skill in the art will understand that when the peaks 120 andvalleys 125 of the surface coating 115 are unevenly spaced, and whenthere is a significant height different between the top of peaks 120 andthe bottom of valleys 125, the resulting surface will be rough, and theslip resistance will be high. In some embodiments of this disclosure,therefore, the height difference between peaks 120 and valleys 125 canbe large and the variation in height and spacing can be sufficient toprovide high slip resistance. In addition, those of skill in the artwill understand that when the change in height from the peaks 120 andvalleys 125 of the surface coating 115 occurs in a relatively smoothmanner over a wide enough distance, debris can be more easily removedfrom between the peaks 120 and valleys 125, and clean-ability will behigh. In some embodiments, therefore, the peaks 120 and valleys 125 canbe far enough apart with sufficiently smooth transitions to provide highclean-ability. Thus, in some embodiments, the change in height from thepeaks 120 and valleys 125 can be large enough to provide high slipresistance and the distance between peaks 120 and valleys 125 can be farenough to provide high clean-ability. More specifically, the change inheight from the peaks 120 and valleys 125 can be large enough to providea DCOF at or above 0.60 and the distance between peaks 120 and valleys125 can be far enough to provide a clean-ability ΔE of less than orequal to 1.0.

In some embodiments, for example, the DCOF of the surface of the tile100, specifically the surface coating 115 of the tile 100, can rangefrom 0.60 to 0.95. In some embodiments, the DCOF can range from 0.60 to0.75. In some embodiments, the DCOF can range from 0.65 to 0.75. In someembodiments, the DCOF can range from 0.60 to 0.80. In some embodimentsthe clean-ability ΔE of surface of the tile 100, specifically thesurface coating 115 of the tile 100, can range from 0.2 to 1.0.Moreover, in some embodiments, the clean-ability ΔE can range from 0.5to 1.0. In some embodiments, the clean-ability ΔE can range from 0.6 to1.0. In some embodiments, the clean-ability ΔE can range from 0.8 to1.0.

FIGS. 2A-2C depict readings from an interferometer that illustrate thesurface structure of an exemplary tile 100 in accordance with thisdisclosure. As those of skill in the art will understand, aninterferometer is a device capable of determining the surface structureof a material by measuring the phase difference between similarelectromagnetic waves. FIG. 2A is an interferometer output thatillustrates a three-dimensional view of the surface structure. FIG. 2Bis an interferometer output that illustrates a two-dimensional, overheadview. FIG. 2C is a graph of the surface structure generated by theinterferometer that more clearly shows the peaks 120 and valleys 125over a given portion of the surface.

FIGS. 3A-3C show readings from an interferometer that illustrates thesurface structure of a standard tile. Like FIG. 2A, FIG. 3A is aninterferometer output that illustrates a three-dimensional view of thesurface structure. FIG. 3B, similar to FIG. 2B, is an interferometeroutput that illustrates a two-dimensional, overhead view. And similar toFIG. 2C, FIG. 3C is a graph generated by the interferometer that moreclearly shows the peaks and valleys over a given portion of the surface.Comparing these FIGS. 2A-2C and 3A-3C, one can see that neighboringpeaks 120 and valleys 125 have a larger height differential in FIGS.2A-2C, increasing DCOF and slip resistance. Moreover, the transitionbetween peaks 120 and valleys 125 is smoother in FIGS. 2A-2C, decreasingclean-ability ΔE and increasing clean-ability.

Those of skill in the art to which this disclosure pertains willunderstand that there are several variables that can be measured by aninterferometer. The peak-to-valley distance, or PV, is the averagemaximum distance from a peak of the surface structure to a neighboringvalley. RMS is the root mean square roughness and is an indication ofthe standard deviation of the peak-to-valley height measurements for agiven area of a tile. The Ra is the average roughness and an indicatorof the deviation from the reference plane. As those of skill in the artwill understand, the reference plane is a plane where the integral ofthe three-dimensional surface of a tile is equal to zero. Thus, the areabetween the reference plane and the measured surface has two equivalentsections, one is where the measured surface is above the reference planeand the other is where the measured surface is below the referenceplane.

The inventors of the subject matter disclosed herein performed severaltests, and in one set of tests, five tile 100 samples in accordance withthis disclosure, as well as five standard tile samples were measured byan interferometer. The average and the standard deviation of the PV,RMS, and Ra were then calculated. Table 1 shows the results.

TABLE 1 Measurement Average St. Dev Tile as taught by this Disclosure PV(μm) 66.32 14.87 RMS (μm) 12.08 2.54 Ra (μm) 10.2 3.08 Standard Tile PV(μm) 70.06 16.26 RMS (μm) 10.72 1.06 Ra (μm) 8.69 0.93

Table 2 shows the high and low values for the same samples.

TABLE 2 Measurements Low High Tile as taught by this Disclosure PV (μm)50 80 RMS (μm) 11.5 14 Ra (μm) 9.5 13 Standard Tile PV (μm) 50 80 RMS(μm) 9 11 Ra (μm) 7 9

Table 1 and Table 2 show that the PV for the tile 100 of the presentdisclosure can be comparable to the conventional tile. The RMS and Ra,however, can be larger for the tile 100 as taught by this disclosure.These measurements indicate that the surface structure has a largerinter-facial surface area due to a larger distribution of peaks 120 andvalleys 125. This larger inter-facial surface area improves the slipresistance of the tile 100 compared to traditional tiles. As those ofskill in the art will understand, a material with a larger inter-facialsurface area will typically be more difficult to slide an object acrossthan the same material of the same size with a smaller inter-facialsurface area. The larger RMS, and Ra can be seen by comparing FIGS. 2A,2B, and 2C, to FIGS. 3A, 3B, and 3C. The smoother transitions betweenpeaks 120 and valleys 125 can also be seen.

In some embodiments, the average RMS of a tile 100 of this disclosurecan range from 5 μm to 20 μm. In some embodiments, the average RMS canrange from 11 μm to 14 μm. In some embodiments, the average RMS canrange from 11.5 μm to 12.6 μm, and in some embodiments the average RMScan range from 11.9 μm to 12.2 μm. In some embodiments, the average Raof a tile 100 of this disclosure can range from 5 μm to 20 μm. In someembodiments, the average Ra can range from 9.0 μm to 16 μm. In someembodiments, the average Ra can range from 9.5 μm to 11 μm, and in someembodiments the average Ra can range from 9.7 μm to 10.7 μm. In someembodiments, the RMS of a tile 100 of this disclosure can be 11.5 orgreater. In some embodiments, the Ra of a tile 100 of this disclosurecan be 9.5 or greater.

The PV, RMS, and Ra of tiles 100 of the present disclosure are notlimited by the values in Table 1 and Table 2. Rather, these tables showexemplary results and measurements. In some embodiments, for example,the PV of a tile can range from 30 μm to 100 μm. Likewise the RMS canrange from 5 μm to 20 μm, and the Ra can range from 5 μm to 20 μm.

As those of skill in the art will understand, the surface structure of atile 100 can be determined, at least in part, by a surface coating 115.In some embodiments, the surface coating 115 can comprise a base formula130 and one or more particulates 135 dispersed in the base formula. Thechemical and particulate 135 make-up of the surface coating 115, alongwith the properties the surface coating 115 exhibits, can enable thesurface structure, such as the peaks 120 and valleys 125, of the finalproduct to form in a manner that provides high slip resistance and highclean-ability.

As described above, embodiments of the present invention are applicableto tile applications. In some embodiments, for example, a tile surfacewith high clean-ability and high slip resistance can be created using asurface coating 115 with solid particles 135 dispersed in the coating.The surface coating 115, or similar coatings, can also be used withother types of flooring. For example, in some embodiments, a surfacecoating 115 in accordance with this disclosure can be applied to a woodfloor, concrete floor, or other non-tile surface to provide highclean-ability and high slip resistance.

In some embodiments, the chemistry of the base formula 130 can beimportant to the final surface characteristics of the tile 100. In someembodiments, for example, the chemistry of the base formula 130 can beimportant at least because the base formula 130 should maintain asufficiently high molten viscosity to support any particles 135suspended within the base formula 130.

While the chemical make-up of the base formula 130 can vary, anexemplary base formula 130 is described in Table 3 below. The componentsof the exemplary base formula 130, which can be combined to produce thechemical make-up, are also shown. The percentages shown in Table 3 areweight percentages based upon the total weight of the dried base formula130 without added particles 135.

TABLE 3 Base Formula Chemical Base Formula Make-up Components K₂O 2.63-3.22% Frit 50-60% Na₂O  3.30-4.30% Clay 10-18% CaO  9.00-13.00%Flux 20-30% MgO  0.08-0.24% Stabilizer  1-3% BaO  1.00-1.40% P₂O₅   0-0.30% ZnO  5.87-6.35% Al₂O₃ 20.23-28.8% ZrO₂  1.20-1.90% Fe₂O₃ 0.1-0.26% SiO₂ 42.63-52.8% TiO₂  0.04-0.11% H₂O  1.00-2.50%

The chemical make-up of the base formula 130, however, is not limited bythe values in Table 3. Rather, Table 3 shows an exemplary composition.In some embodiments, for example, K₂0 can be present in an amountranging from 1% to 6%, Na₂O can be present in an amount ranging from 1%to 8%, and CaO can be present in an amount ranging from 3% to 20%. Insome embodiments, MgO can be present in an amount ranging from 0.03% to0.5% and BaO can be present in an amount ranging from 0.3% to 5%.Moreover, in some embodiments, P₂O₅ can present in an amount rangingfrom 0% to 2%, ZnO can be present in an amount ranging from 2% to 11%,Al₂O₃ can be present in an amount ranging from 5% to 40%, ZrO₂ can bepresent in an amount ranging from 0.4% to 5%, and Fe₂O₃ can be presentin an amount ranging from 0.03% to 0.5%. In some embodiments, SiO₂ canbe present in an amount ranging from 10% to 80%, TiO₂ can be present inan amount ranging from 0.01% to 0.5%, and H₂O can be present in anamount ranging from 0.3% to 10%. Additionally, in some embodiments, fritcan be present in an amount ranging from 30% to 90%, clay can be presentin an amount ranging from 1% to 50%, flux can be present in an amountranging from 5% to 50%, and stabilizer can be present in an amountranging from 0.1% to 10%.

Thus, in some embodiments, the surface coating can have a composition of1-4 wt % potassium, 1-6 wt % sodium, 5-20 wt % calcium, 3-10 wt % zinc,15-40 wt % aluminum, and 30-60 wt % silicon. The surface coating canhave a composition of 2-4 wt % potassium, 2-5 wt % sodium, 7-15 wt %calcium, 3-8 wt % zinc, 18-35 wt % aluminum, and 40-60 wt % silicon. Thesurface coating can have a composition of 2.5-3.5 wt % potassium, 3-5 wt% sodium, 8-14 wt % calcium, 4-7 wt % zinc, 20-30 wt % aluminum, and40-55 wt % silicon. In some embodiments, the surface coating can contain1-4 wt % potassium, 2-4 wt % potassium, or 2.5-3.5 wt % potassium. Insome embodiments, the surface coating can contain 1-6 wt % sodium, 2-5wt % sodium, or 3-5 wt % sodium. In some embodiments, the surfacecoating can contain 5-20 wt % calcium, 7-15 wt % calcium, 8-14 wt %calcium, or 9-13 wt % calcium. In some embodiments, the surface coatingcan contain 3-10 wt % zinc, 3-8 wt % zinc, 4-7 wt % zinc, or 5-6.5 wt %zinc. In some embodiments, the surface coating can contain 15-40 wt %aluminum, 18-35 wt % aluminum, or 20-30 wt % aluminum. In someembodiments, the surface coating can contain 30-60 wt % silicon, 40-60wt % silicon, or 40-55 wt % silicon. In each instance, the elementalcomposition is recited as the percent weight of the most common oxide,i.e. the oxides described above. In some embodiments, the surfacecoating can also contain less than 2 wt % of magnesium, barium, iron,and titanium. In some embodiments, the surface coating can contain lessthan 1 wt % of magnesium, barium, iron, and titanium, or less than 0.5wt % of magnesium, barium, iron, and titanium. Also, in someembodiments, the surface coating can contain less than 2 wt % zirconium.In some embodiments, magnesium, barium, iron, and titanium can each bepresent in at least about 0.02 wt %.

In some embodiments, other components can be present, and/or some of thecomponents listed in Table 3 can be absent. In other words, the chemicalmake-up of the base formula 130 is variable both by the componentsincluded and the amount of each component, and is not limited by theexample shown in Table 3.

In some embodiments, the base formula 130 is created by processingvarious materials in water. The materials used in the base formula 130can be somewhat flexible or variable. In some embodiments, the baseformula 130 can be a glaze, such as NB-0022 glaze. Most glazes have afrit (processed glass with a specific mineralogy), clay (alumina withminerals), and an opacifier (a material with a large percentage ofZirconium Oxide). The base formula 130 can incorporate the various rawmaterials by their weight. In some embodiments, the materials are putinto a ball mill. As those of skill in the art will understand, a ballmill is a type of grinder used to grind materials into a very finepowder which allows for more uniform behavior. Certain amounts of water,along with suspension agents, can also be added to the ball mill. Thesuspension agents can help keep the particles dispersed and suspendedwithin the water during processing. Once the base formula 130 has beenground, it can be removed from the ball mill and applied onto asubstrate.

As described above, solid particles 135 can be added to the base formula130 to provide the surface coating with desirable surface properties,such as high slip resistance while maintaining high clean-ability. Theparticles 135 can be added to the base formula 130 at various stages. Insome embodiments, for example, the particles 135 can be added while thecomponents of the base formula 130 are being combined, such as in a ballmill. In some embodiments, the particles 135 can be added to the baseformula 130 and mixed into the base formula 130 after the base formula130 is made. In these embodiments, the particles 135 can be combinedwith the base formula 130 in the ball mill or after the base formula 130is removed from the ball mill.

In some embodiments, the solid particles 135 can comprise analumina-zirconium-silicate, also known as AZS. AZS can enable thesurface coating 115 to have a large temperature stability range and canalso prevent the surface coating 115 from becoming opaque. In someembodiments, up to 80% by weight of the solid particles 135 can be AZS.In some embodiments, between 40% and 95% of the solid particles 135 canbe AZS. In some embodiments, the remaining percentage of the solidparticles 135, i.e., those that are not AZS, can comprise alumina, suchas tabular alumina. Thus, in some embodiments, the ratio of AZSparticles 135 to other particles 135 (such as tabular alumina particles135), by weight, can be 4:1 or approximately 4:1. In some embodiments,however this ratio can be from 3:1 to 5:1.

In some embodiments, the AZS that is used can be sold under the tradename Zirduro. In some embodiments, Zirduro can comprise a zirconium andsilicon oxide known by the trade name Zircon.

In some embodiments, the tabular alumina can be calcined alumina. Insome embodiments, tabular alumina can be recrystallised or sinteredα-alumina. Tabular alumina can also be flat tablet-shaped crystals. Insome cases, tabular alumina can be produced by pelletizing, extruding,or pressing calcined alumina into shapes and then heating these shapesto a temperature just under their fusion point. After calcination, thesintered alumina can be used for some applications, e.g., catalyst beds,or they can be crushed, screened, and ground to produce a wide range ofsizes. As the material has been sintered it can have an especially lowporosity, high density, low permeability, good chemical inertness, highrefractoriness and can be especially suitable for refractoryapplications.

In some embodiments, instead of or in addition to the AZS and tabularalumina, the solid particles 135 can comprise alumina trihydrate, alsoknown as ATH. In some embodiments, the ATH can comprise aluminatrihydrate powder. Like the AZS and tabular alumina, the ATH can beadded in varying amounts, and thus several ratios of AZS to ATH totabular alumina are envisioned. In some embodiments, for example,between 35% and 55% by weight of the solid particles 135 can be AZS,between 35% and 55% of the solid particles 135 can be ATH, and between5% and 20% can be tabular alumina. In some embodiments, between 43% and46% of the solid particles 135 can be AZS, between 43% and 46% of thesolid particles 135 can be ATH, and between 9% and 13% can be tabularalumina. Thus, in some embodiments, the ratio of AZS particles 135 toATH particles 135 to other particles 135 (such as tabular aluminaparticles 135), by weight, can be 4:4:1 or approximately 4:4:1. In someembodiments, however this ratio can be from 3:3:1 to 5:5:1, such as, forexample and not limitation, 3:4:1, 3:5:1, 4:3:1, 4:4:1, 4:5:1, 5:3:1,5:4:1. Thus, in some embodiments, AZS and ATH particles 135 can bepresent in substantially the same amount, by weight, and tabular aluminaparticles 135 can be present in a smaller amount.

While the chemical make-up of the mixture of particles 135 can vary, anexample is provided in Table 4 below for an AZS and tabular aluminamixture. The percentages shown in Table 4 are weight percentages basedupon the total weight of the mixture of particles 135.

TABLE 4 Particle Composition Al₂O₃ 42.0-53.0% ZrO₂ 29.0-36.5% CaO 0.0-0.4% SiO₂  9.5-16.0% HfO₂ 0.00-0.65% Na₂O  1.0-2.5% H₂O  1.0-3.0%

The chemical make-up of the mixture of particles 135, however, is notlimited by the values in Table 4. Rather, Table 4 shows an exemplarycomposition. In some embodiments, for example, Al₂O₃ can be present inan amount ranging from 20% to 80%, ZrO₂ can be present in an amountranging from 10% to 50%, CaO can be present in an amount ranging from 0%to 5%, and SiO₂ can be present in an amount ranging from 3% to 25%. Insome embodiments, HfO₂ can be present in an amount ranging from 0% to5%, Na₂O can be present in an amount ranging from 0.1% to 15%, and H₂Ocan be present in an amount ranging from 0.1% to 15%.

In some embodiments, other components can be present in the mixture ofparticles 135, and/or some of the components listed in Table 4 can beabsent. In other words, the chemical make-up of the mixture is variableboth by the components included and the amount of each component, and isnot limited by the example shown in Table 4.

Having a plurality of types of particles 135, such as AZS particles 135,ATH particles 135, and tabular alumina particles 135, can improve thesurface structure by introducing a desirable size distribution ofparticles 135 and desirable spacing of particles 135 that, incombination with the properties of the particles 135, produces highclean-ability and high slip resistance. Moreover, in some embodiments,these materials can interact with the base formula 130 in a manner thatprovides a desired amount of dissolution to form the peaks 120, valleys125, and spacing so that the surface coating 115 is both highlycleanable and slip resistant.

In some embodiments, the size of the particles 135 and size distributionof the particles 135 can play a role in the clean-ability and slipresistance of the final tile 100. An exemplary particle sizedistribution is shown in Table 5. Table 5 was generated by a particlesize analysis machine, and, specifically, by a dynamic light scatteringtechnique. In Table 5, the channel diameter is the diameter throughwhich a corresponding percentage of the particles 135 are able to passthrough. It can also be looked at as if the particles are being filteredout when they cannot pass through a channel diameter of a certain size.

TABLE 5 Channel Diameter % Less Than (Lower) μm 0.18 0.3752 10 1.0149225 2.33999 50 7.25089 75 14.167 90 20.0436 100 33.011

In addition, in some embodiments, the particle size distribution of thesolid particles can be the same as or similar to that shown in FIG. 4.Table 5 and FIG. 4 are both examples, and do not limit the sizes or sizedistributions of particles 135. For example, as shown in Table 5,substantially all of the particles 135 have a channel diameter smallerthan 33.011 μm, but this is not meant to limit the size distributionscontemplated by this disclosure.

Both Table 5 and FIG. 4 show that there can be a relatively highpercentage of larger particles 135. These larger particles 135 can helpimprove the slip resistance of the final product by providing higher andbetter-defined peaks 120 and lower and better-defined valleys 125.Moreover, the interplay between the make-up of the base formula 130 andthe larger particles 135 can space the particles 135 such that theyprovide the smooth transitions between peaks 120 and valleys 125 thatcan provide high clean-ability.

In some embodiments, the solid particles can make up from 2% to 10% ofthe weight of the surface coating 115. In some embodiments, the solidparticles can make up from 7% to 15% of the weight of the surfacecoating 115. In some embodiments, the solid particles can make up from1% to 25% of the weight of the surface coating 115.

After the surface coating 115 is completed, it can be sprayed onto asubstrate, such as a raw tile or wood floor-board. In some embodiments,such as embodiments involving a tile 100, the tile 100 can have anoptional base coating 110, such as a ceramic coating. In someembodiments, the base coating 110 can have a high enough moltenviscosity to keep the particles 135 in the surface coating 115 suspendedon top of the base coating 110 throughout manufacturing and until afinished tile 100 is formed. In tile applications, the base coating 110can have a high enough molten viscosity to keep the particles 135suspended on top of the base coating 100 during firing. In someembodiments, the minimum viscosity that can support particles 135throughout firing is in the area of e⁵ or 2.71828⁵ Pa*s. This value isnot limiting, however, as higher or lower viscosities can be required oracceptable. One important factor, though, is that the base coatingmaintains a sufficient viscosity at peak firing temperature in order tosupport the particles 135 in the surface coating 115.

In addition to the advantages described above, tiles 100 and coatings inaccordance with this disclosure can be fired across a range oftemperatures. Specifically, the surface coatings 115 of the presentdisclosure, such as those described above, can be fired above 1150degrees Celsius. It is desirable to fire surface coatings 115 at thesehigher temperatures because the higher temperatures yield a stronger,more resilient coating. However, traditional surface coatings cannot befired at these high temperatures because suspended particles would meltand the desired surface characteristics would not be achieved. Theinventors of the present disclosure have found, however, that firing thesurface coatings 115 described above at higher than 1150 degrees Celsiusdoes not melt the particles 135 due to unique interactions between thebase formula 130 and particles 135. In fact, the surface coating 115 canbe fired at a temperature as high as 1250 degrees Celsius withoutmelting the particles 135. Thus, the surface coatings 115 of the presentdisclosure can provide a stronger, more resilient coating withoutsacrificing the desired surface characteristics of high clean-abilityand high slip resistance.

In some embodiments, a tile 100 in accordance with the presentdisclosure can be coated with a surface coating 115 and fired in twostages—a low firing and a high firing. In some embodiments, the lowfiring can be approximately 25 minutes at about 1150 degrees Celsius.After the low firing, the high firing can take place for approximately60 minutes at about 1230 degrees Celsius. In some embodiments, however,the low firing can be for between 10 and 40 minutes at between 1000 and1170 degrees Celsius, and the high firing can be for between 30 and 90minutes at between 1150 and 1300 degrees Celsius. These conditions canproduce a finished tile 100 with high clean-ability and high slipresistance in accordance with this disclosure.

FIG. 5 and FIG. 6 illustrate the properties of a desirable base coating110 and an undesirable base coating 110. FIG. 5 shows the sinteringproperties and viscosity properties of a desirable base coating 110 overa range of firing temperatures. As one of skill in the art willunderstand, the base coating 110 of FIG. 5 maintains a sufficiently highviscosity of about e⁵ to and above 1275-1300 degrees Celsius. Thus, asshown, the particles of the base coating 110 can sinter and theviscosity can remain high at high temperatures. As shown in FIG. 6, anundesirable base coating 110 does not maintain a sufficiently highviscosity at it approaches 1250 degrees Celsius or 1300 degrees Celsius.FIG. 7 shows a comparison of viscosities for a desirable base coating110 and an undesirable base coating 110. Again, the desirable basecoating 110 maintains a sufficiently high viscosity to and above 1275degrees Celsius, whereas the undesirable base coating 110 does not.Those of skill in the art will understand that a tile 100 can be madewith an undesirable base coating 110, but the results will generally notbe as advantageous as with a desirable base coating 110.

Embodiments of the present disclosure can comprise a method formanufacturing flooring, such as one or more tiles 100. In someembodiments, a piece of flooring is made using pressed or moldedmaterial to form a substrate 105, and the flooring is optionally coatedwith one or more layers of base coating 110. A surface coating 115 inaccordance with the present disclosure is then added on top of the basecoating 110, if present, or on top of the substrate 105, if there is nobase coating 110. The flooring can then be fired.

In some embodiments, the surface coating 115 can be applied to a tile100 by a spray gun or spray booth. In another instance, the surfacecoating 115 can be applied by cascading the surface coating 115 onto theflooring. In another instance, the surface coating 115 can be applied bya controlled splattering of the surface coating 115, which can be doneby a double disc applicator known within the ceramics industry.

In some embodiments, after applying the surface coating and firing, theflooring will be ready for processing and then packaging.

While certain systems and methods related to composite tile systems andmethods have been disclosed in some exemplary forms, many modifications,additions, and deletions may be made without departing from the spiritand scope of the system, method, and their equivalents. The embodimentsdisclosed herein are further capable of other embodiments and of beingpracticed and carried out in various ways. Also, it is to be understoodthat the phraseology and terminology employed herein are for thepurposes of description and should not be regarded as limiting theclaims.

Accordingly, those skilled in the art will appreciate that theconception upon which the application and claims are based may bereadily utilized as a basis for the design of other devices, methods,and systems for carrying out the several purposes of the embodiments andclaims presented herein. It is important, therefore, that the claims beregarded as including such equivalent constructions.

What is claimed is:
 1. A floor tile comprising: a substrate; and asurface coating provided on an upper surface of the substrate, thesurface coating comprising: a base formula; and particles, wherein thebase formula comprises a glaze, wherein the particles comprise aluminatrihydrate, wherein the base formula and the particles remain separateafter firing, wherein the floor tile is a ceramic floor tile, andwherein the particles make up from 1% to 7% of the weight of the surfacecoating after firing.
 2. The floor tile of claim 1, wherein the surfacecoating further comprises particles comprising tabular alumina.
 3. Thefloor tile of claim 1, wherein the surface coating further comprisesparticles comprising alumina-zirconium-silicate.
 4. The floor tile ofclaim 3, wherein the weight of particles comprisingalumina-zirconium-silicate and the weight of particles comprisingalumina trihydrate is substantially equal.
 5. The floor tile of claim 1,wherein the surface coating further comprises particles comprisingalumina-zirconium-silicate and particles comprising tabular alumina. 6.The floor tile of claim 5, wherein the weight ratio of particlescomprising alumina-zirconium-silicate to particles comprising aluminatrihydrate to particles comprising tabular alumina is from 3:3:1 to5:5:1.
 7. The floor tile of claim 5, wherein the weight ratio ofparticles comprising alumina-zirconium-silicate to particles comprisingalumina trihydrate to particles comprising tabular alumina isapproximately 4:4:1.
 8. The floor tile of claim 1, wherein substantiallyall of the particles have a diameter of less than 33.011 microns.
 9. Thefloor tile of claim 1, wherein about 90% of the particles have adiameter of less than 20.0436 microns.
 10. The floor tile of claim 1,wherein about 50% of the particles have a diameter of less than 7.25089microns.
 11. The floor tile of claim 1, further comprising a basecoating disposed substantially between the substrate and the surfacecoating.
 12. The floor tile of claim 11, wherein the base coatingsupports the surface coating during a firing process, wherein at least aportion of the firing process occurs at above 1150 degrees Celsius. 13.The floor tile of claim 1, wherein the surface coating provides aclean-ability ΔE of 0.6 to 1.0 and a dynamic coefficient of friction of0.60 to 0.95.
 14. The floor tile of claim 1, wherein the glaze comprisesa frit, a clay, and an opacifier.
 15. The floor tile of claim 1, whereinan average RMS of the floor tile is from 11.5 microns to 12.6 microns.16. The floor tile of claim 1, wherein an average Ra of the floor tileis from 9.5 microns to 11.0 microns.
 17. The floor tile of claim 1,wherein an average RMS of the floor tile is from 11.5 microns and 12.6microns and an average Ra of the floor tile is from 9.5 microns and 11.0microns.